isgraph(3)

1ISALPHA(3)                 Linux Programmer's Manual                ISALPHA(3)
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NAME

6       isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower,
7       isprint, ispunct, isspace, isupper, isxdigit - character classification
8       routines
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SYNOPSIS

11       #include <ctype.h>
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13       int isalnum(int c);
14       int isalpha(int c);
15       int isascii(int c);
16       int isblank(int c);
17       int iscntrl(int c);
18       int isdigit(int c);
19       int isgraph(int c);
20       int islower(int c);
21       int isprint(int c);
22       int ispunct(int c);
23       int isspace(int c);
24       int isupper(int c);
25       int isxdigit(int c);
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27   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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29       isascii():
30           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE
31       isblank():
32           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
33           _POSIX_C_SOURCE >= 200112L;
34           or cc -std=c99
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DESCRIPTION

37       These functions check whether c,  which  must  have  the  value  of  an
38       unsigned char or EOF, falls into a certain character class according to
39       the current locale.
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41       isalnum()
42              checks for an alphanumeric character; it is equivalent to (isal‐
43              pha(c) || isdigit(c)).
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45       isalpha()
46              checks  for an alphabetic character; in the standard "C" locale,
47              it  is  equivalent  to  (isupper(c)  ||  islower(c)).   In  some
48              locales,  there may be additional characters for which isalpha()
49              is true—letters which are neither upper case nor lower case.
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51       isascii()
52              checks whether c is a 7-bit unsigned char value that  fits  into
53              the ASCII character set.
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55       isblank()
56              checks for a blank character; that is, a space or a tab.
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58       iscntrl()
59              checks for a control character.
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61       isdigit()
62              checks for a digit (0 through 9).
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64       isgraph()
65              checks for any printable character except space.
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67       islower()
68              checks for a lower-case character.
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70       isprint()
71              checks for any printable character including space.
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73       ispunct()
74              checks  for  any  printable character which is not a space or an
75              alphanumeric character.
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77       isspace()
78              checks for white-space  characters.   In  the  "C"  and  "POSIX"
79              locales,  these  are:  space,  form-feed ('\f'), newline ('\n'),
80              carriage return ('\r'), horizontal tab ('\t'), and vertical  tab
81              ('\v').
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83       isupper()
84              checks for an uppercase letter.
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86       isxdigit()
87              checks for a hexadecimal digits, that is, one of
88              0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F.
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RETURN VALUE

91       The  values  returned  are  nonzero  if  the character c falls into the
92       tested class, and a zero value if not.
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CONFORMING TO

95       C99, 4.3BSD.  C89 specifies all of these functions except isascii() and
96       isblank().  isascii() is a BSD extension and is also an SVr4 extension.
97       isblank() conforms to POSIX.1-2001 and C99 7.4.1.3.  POSIX.1-2008 marks
98       isascii()  as  obsolete,  noting  that  it cannot be used portably in a
99       localized application.
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NOTES

102       The details of what characters belong into which class  depend  on  the
103       current  locale.  For example, isupper() will not recognize an A-umlaut
104       (Ä) as an uppercase letter in the default C locale.
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COLOPHON

113       This  page  is  part of release 3.53 of the Linux man-pages project.  A
114       description of the project, and information about reporting  bugs,  can
115       be found at http://www.kernel.org/doc/man-pages/.
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119GNU                               2010-09-20                        ISALPHA(3)